$\begingroup$By correct expression you mean an equation, right? Otherwise one could simply take away the = and it would be a correct expression as there would be no mistake in it.$\endgroup$
– Zelphir KaltstahlMar 28 '17 at 11:30

$\begingroup$This is a good answer too, maybe even better than mine... the only flaw I see is that the 9s are different in shape (I don't care for the smaller 4)$\endgroup$
– mauMar 27 '17 at 20:54

$\begingroup$@mau Don't complain, you said "This is not a digital display, so digits may be built differently"$\endgroup$
– mbomb007Mar 27 '17 at 21:50

$\begingroup$@mau, proposed another solution with no difference between same digits, but I do not like the introduced spacing in it ;)$\endgroup$
– kamenfMar 27 '17 at 22:39

$\begingroup$@mbomb007 indeed I did not complain for the 4...$\endgroup$
– mauMar 28 '17 at 9:02

$\begingroup$I believe what the OP meant was that digits can be built from non-standard digital display numbers, but that digit must be built uniformly throughout the entire equation (the first 9 doesn't have the bottom part like the others).$\endgroup$
– Long NguyenMar 28 '17 at 19:05

Initial equation: 1 = 850 - 9 - 6
Move a matchstick from the = to the centre -: 1 - 850 = 9 - 6
Move the other matchstick from what was the = to the 6: 1 850 = 9 - 8
Finally, move the top matchstick of the 1 down to immediately below the bottom matchstick of that 1. This changes the vertical alignment of the expression: 1850 = 9 - 8
And of course, a superscript means exponentiation; 1 to the power of 850 and 9 minus 8 are both 1.

Change the 6 and 9 on the right to a 9 and a 6 (one step each, two total). Then take the minus sign between the 9 and 6, and move it to the 5 to create a 9. Now rotate it 180 degrees (aka look upside-down). You get 69-068=1.

$\begingroup$exponentiation was part of my own solution, but since this is not a display I am not sure E is allowed. (Then again, there is not an official solution, of course)$\endgroup$
– mauMar 28 '17 at 9:05

Rotate the first minus sign by 45 degrees (1 movement). Then take a vertical stick on the left of the 8 and move it to convert this minus sign into a multiply sign (2 movements). Lastly, remove the other vertical stick on the left of the 8, which converts the 8 into a 3 (3 movements).

You will then have

9 X 6 - 053 = 1

Which is correct!!

NOTE: One match stick is removed completely, which isn't against the rules, but not be in the spirit of the puzzle.

$\begingroup$@mau how can you obtain that by moving only 3 match sticks? Note, I counted the removal of a match stick as a move.$\endgroup$
– TreninMar 28 '17 at 11:49

$\begingroup$@mau How about dropping the final stick ontop of he minus sign using two sticks for the minus? It isn't removing the stick, just putting it somewhere that doesn't change the equation. In fact, you can put it over any matchstick you want so long as it lines up correctly.$\endgroup$
– TreninMar 28 '17 at 11:55

If multiplication is allowed 1 = 055 - 9 x 6, First use the middle of the 8 to make the x and a 0, then take 2 sticks from the 0, use one to make it into a 5 and then add the last stick to the 1 as a hat.

$\begingroup$Very true, in that case just add a hat to the 1, I will edit my answer$\endgroup$
– Gareth ShepherdMar 27 '17 at 20:36

$\begingroup$Also I was not sure if the slight rotation of the one stick to match with the multiplication sign would count as a move or not, I assumed it would not$\endgroup$
– Gareth ShepherdMar 27 '17 at 20:39

There were many nice solutions to the puzzle, and I have to decide which is the best one. Anyway, here there is my own:

Take the three bottom matches from the 0. Add one to the three remaining so to have a small zero as exponent; add another to the first minus to have another equal sign; add the last one to the 6, obtaining an 8.
The final result is $1 = 85^0 = 9-8$
I wrote "an expression", not "an equation", so Scott has a point (but a single number is not "correct"), so that I can use two equal signs.

$\begingroup$To be fair, your own answer looks good to me. No weird spaces, no leading zeroes, no weird shapes as numbers or symbols. My answer, while a stretch (with the E operator), also fulfilled my own criteria :)$\endgroup$
– PokemonMar 29 '17 at 2:03

Pick up the two matches making the = sign, and one of the two minus signs. Turn them into a 7 at the end of the statement.

So that evaluates to

18509-67

i.e.

18442

This works because

Anything is truthy, unless it is explicitly defined to be falsey. Falsey statements are false, 0, "", null, undefined, and NaN. 1+1=3 evaluates to false, but 2 is simply the integer 2. Non 0 integers are one example of a truthy value here.

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